Due to the development of technologies, a user may use a variety of electronic devices, and the electronic devices should work normally without an error occurring. However, it may be difficult for a user to check an error of an electronic device as the electronic device is complex.
If the electronic device keeps working abnormally, components of the electronic device may become damaged and the electronic device may break down.
A lifespan of an electronic device may improve by detecting an error of the electronic device at an early stage. In order to detect an error of the electronic device, a component thereof, such as a circuit, may be examined.
When a resonance circuit is used in an electronic device, an error of the resonance circuit may be detected so that dangers arising due to resonance of the resonance circuit are reduced.
An electromagnetic induction fusing device may employ an inverter controlling method to detect an error of the resonance circuit. Characteristics of a resonance circuit may be determined based on System resistance Rs(Ω), coil inductance L(H), and capacitor capacitance C(F).
It is effective to drive a resonance circuit in its resonance frequency, but the resonance frequency may vary due to changes of characteristics of each component.
When a driving frequency is lower than a resonance frequency, excess current may flow through a resonance circuit or a circuit electrically connected to the resonance circuit, which may result in damage to the circuits. Therefore, it is common to drive the resonance circuit at a higher frequency than its resonance frequency. However, the resonance frequency itself may rise somehow, and so the resonance circuit may be driven at a lower frequency than its resonance frequency.
Technologies to solve such problems are disclosed in following references:    Japanese Unexamined Patent Application Publication No. 03-190082    Japanese Unexamined Patent Application Publication No. 2008-053070    Japanese Unexamined Patent Application Publication No. 2008-197475